UBC Theses and Dissertations
Studies on reproductive characteristics and artificial insemination in captive Mallard Ducks (Anas platyrhynchos) Stunden, Carolyn Elizabeth
Several studies were conducted to evaluate the use of artificial insemination (AI) as a means to improve the reproductive success of hand-reared wild-strain Mallards (Anas platyrhynchos). The effects of age, mate choice and isolation on reproductive parameters of captive Mallards were studied. Eighteen adult and yearling hens were allowed physical, visual-auditory or auditory only contact with drakes. In addition, another 28 yearling hens were placed (17 random, 15 self-chosen) with yearling drakes. Age of males was a key determinant in Mallard reproductive success, specifically egg fertility. Self-chosen pairs performed better than randomly assigned pairs and isolation of hens from drakes did not affect egg production. The data suggests that artificial breeding is needed to supplement natural mating and increase egg fertility in yearlings. Since egg fertility was generally low in captive held yearling Mallards, comparisons between captive and free-flying Mallard drakes were made to assess differences in gonadal development. Measurements of numerous parameters indicated that, gonadal development was suppressed in captive drakes of both age classes. For the captive drakes, seasonal profiles of testosterone (T) levels and semen characteristics were determined in yearlings and adults. Plasma T concentrations increased from basal levels in March, peaked in April and decreased to basal levels in May. The decrease in T concentration to basal level occurred two weeks earlier in yearlings compared to that of adults. Surprisingly, semen volume and semen concentration were not different between the two age groups. Mallards were artificially inseminated by modifying a technique developed for domesticated poultry. Egg fertility obtained with Al was 73%. Thus, these results suggest that Al may indeed be used successfully in propagating wild Mallards. Two poultry semen extenders [Beltsville Poultry Semen Extender (BPSE) and Lake's Poultry Semen Extender (LAKE)] were compared with respect to their effects ..on sperm survival and sperm fertilizing capacity. BPSE and LAKE worked equally well to maintain the semen fertilizing capacity during short-term storage. Last of all, effects of various concentrations of cryoprotectants [glycerol, ethylene glycol (EG), propylene glycol (PG) and sucrose] on the fertilizing capacity of unstored chicken spermatozoa were tested. The addition of sucrose to EG or PG on the viability of frozen- thawed chicken semen was determined. Fertility declined with increasing concentrations of glycerol and sucrose, but not with increasing concentrations of EG and PG. The addition of sucrose (0.2 M) did not improve freeze-thaw protection of EG and PG.
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